Field of the Invention
The present invention relates to an electric heater especially for an automobile vehicle, with an electric heating element, which is connectable to an electric power source, with an insulating element and with a tube with the electric heating element being placed inside the tube and being electrically insulated from the tube, with the tube having at least one opening, through which the insulating element and the electric heating element can be inserted into the tube.
Description of the Background Art
Electric heaters usually have at least one heating element, which can be heated by applying an electric current to the element. The heat is then transported via fins or other thermally conductive parts to a heat sink. The heat sink can thus be heated by the heating element. The heat sink can be represented by a fluid, which flows through a heat exchanger or over the surface of the heat exchanger.
In embodiments that are known in the conventional art the electric heating element, which is advantageously connected to a positive pole and a negative pole of an electrical power source, is positioned between insulating elements before it is placed within a tube or attached to the outer surface of a tube. The insulating elements are used to avoid short circuits between the electric heating element and other structures, by which the electric heating element is surrounded, e.g. the tube or heat transmitting fins. The elements are usually press-fitted with each other to avoid relative movement between the elements. The elements can be press-fitted with each other or glued to each other to avoid relative movement between the elements.
Especially electric heaters within automobile vehicles can be subject to mechanical stress due to the operation of the vehicle. The mechanical stress can lead to relative movement between the insulating elements, the electric heating elements and the surrounding tube. The relative movement can thereby lead to damage at the insulating elements or to a direct contact between the electric heating elements and a structure, which is normally insulated against the electric current of the electric heating element.
This is disadvantageous as a direct contact, which is caused by the relative movement or the damage of the insulating elements, can lead to short circuits, which pose a potential risk for human beings. Short circuits are especially dangerous as human beings can accidently be exposed to an electric shock, which can lead to injuries and possibly death.